In dentistry, addition silicones are the most widely used impression materials. Addition curing silicones are favored as impression materials in dentistry for their high accuracy and dimensional stability.
In U.S. Pat. No. 4,675,959 the use of various surfactants is described, some being the fluoroalkyl polyoxyethylene type. However, no combinations of surfactants are described.
U.S. Pat. No. 6,291,546 describes the use of nonionic surfactants of two types, specifically alkyl ethers and fluoroalkyl ethers like the Zonyl 100 (Dupont) type.
U.S. Pat. No. 7,812,065 describes a combination of a fluoroalkyl ether with a silicone ether defined as “a non-ionic surfactant with a molecular mass of less than 6000 g/mol containing at least one (poly)alkylene oxide group as well as one silicon containing group”. This combination is claimed to give a low contact angle on mixing but not on cured impression material.
U.S. Pat. No. 8,466,210 describes the use of a perfluorinated polyether used in combination with a silicone ether to afford a low contact angle for mixed but not yet cured impression material.
U.S. Pat. No. 8,916,623 describes the use of nonionic surfactants of three types: polyoxyethylene alkyl ethers, silicone alkyl ethers and fluoroalkyl ethers like the Zonyl 100 (Dupont) type. The polyoxyethylene alkyl ethers described therein are end-capped with alkyl groups and do not contain any terminal hydroxyl groups. Combinations of these three surfactant types is reported to give a low contact angle on mixed but not yet cured impression material.
It is necessary, in effectively taking an impression, to be able to easily remove the impression from the dentition without tearing, particularly at thin marginal areas, to preserve fine detail and this property is usually evaluated by measuring tear strength. Linear divinyl PDMS are used in commercial addition silicone based impression materials. U.S. Pat. No. 56,661,222 describes an addition silicone impression material based on quadri-functional polydimethylsiloxane (PDMS) or QM resins. The use of these QM resins provides improved tear strength to the polymerized impression composition by increasing its resulting polymerized crosslink density.
There is a need of an impression material that exhibits a low contact angle before set with adequate tear strength. Moreover this impression material needs to have adequate shelf life stability to be usable upon at least 3 years of storage at room temperature. This can be shown by an accelerated aging test.